Clean up duplicated code bug in RequestTransferURL.

This makes should_replace_current_entry work even when starting from a
WebUI page.  The should_replace_current_entry logic appears broken at
the moment and will be fixed in a followup CL, so I'm deferring the test.

BUG=311721
TEST=Will be in the followup CL that fixes the rest of the bug.

Review URL: https://codereview.chromium.org/45773002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@231370 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 231370